304 Integrating Geochronology and Geochemistry to Decipher the Tectonic Evolution of Orogenic Belts (Posters)

This session focuses on deciphering magmatic, metamorphic, depositional and deformational events recorded in orogenic belts via the integration of geochemistry and geochronology. We welcome contributions from modern applications of analytical methods aimed at unraveling orogenic events worldwide, fostering interdisciplinary discussion.

Wednesday, 22 October 2025
8:00 AM - 5:30 PM
HBGCC, Hall 1

Coats Land, Antarctica and West Texas: Evaluating the Potential Precambrian Link with Radiometric Dating

Paper number: 304-0
Program: Technical Sessions
Time: 8:00 AM – 8:00 AM

Authors

Abstract

Acceptance of traditional notions about the rigidity of continental drift has obscured our understanding of the configuration of southern Laurentia. We sought to help fill this gap by testing the connection between Coats Land, Antarctica and West Texas dating back to the existence of Rodinia. Our team utilized two methods. Method one utilized LA-ICP mass spectrometry to date zircons from Coats Land rhyolite BB4A and Franklin Mountains granite FM107 by comparing ratios of uranium to lead. Data points were then filtered with Iolite 4 and put into IsoplotR to produce a Wetherill concordia diagram that was further filtered. Method two placed the same zircons into an LA-MC-ICP mass spectrometer to determine hafnium isotope compositions. Our hafnium ratios were then plugged into Excel to produce an epsilon hafnium diagram. U-Pb dating derived an age range of 1137.6 +/- 3.5/5.9 Ma for zircons from BB4A and 1128.5 +/- 5.5 Ma for zircons from FM107. Lu-Hf analysis produced epsilon hafnium values for FM107 that were slightly lower than epsilon hafnium values for BB4A, suggesting that FM107 inherited older crust. Our data yields similar ages for Coats Land and West Texas, which is conducive to the idea that they were once connected. This connection aligns with the configuration of Pannotia and provides us with an understanding of the environment of the past that has contributed to events like the Cambrian Explosion. In particular, we’ve gained a better understanding of the supercontinent cycle that has implications for Earth’s climate and biodiversity.

Geological Society of America Abstracts with Programs. Vol. 57, No. 6

doi: 10.1130/abs/2025AM-412472

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